GB668942A - Improved anti-burglary apparatus - Google Patents

Abstract

668,942. Burglar alarm systems. RELYA-BELL BURGLAR & FIRE ALARM CO., Ltd. Feb. 7, 1950. [Feb. 7, 1949] No. 3163/50. Class 118 (i). [Also in Group XVIII] Antiburglary apparatus for articles which are displayed or otherwise accessible to the public comprises an inertia electric contact device which is associated with means to remove the articles to a place of safety. Fig. 1 shows a shop window in which articles B are arranged on a platform which is urged by a spring to rotate about an axis 2, but is retained in position by detent means 8. An inertia operated switch 13 is arranged in contact with the window frame so that vibration of this frame closes the contacts and operates an electromagnet to release the detent means 8. The platform then rotates to discharge ti.e articles into a receptacle or chute, and after rotating 180 degrees may be locked in position by a spring bolt 10 to prevent-access to the articles. A battery, which is continually maintained charged from the main supply, is used to operate the electromagnet. The inertia operated switch may be associated with relays, and may be used in alarm systems, operating on either the closed-circuit or the open-circuit principle. Alarm bells, or a telephone alarm system in which a recorded message is transmitted to a central station may be utilised. The display arrangement may alternatively consist of a cabinet which closes under corresponding conditions of interference, or of platforms which move horizontally or vertically in conjunction with self-locking flaps which operate to prevent access to the: articles. The invention may also be applied to counters or table tops having rotating flaps which operate to discharge the articles into a lower receptacle. A manual or pedal operated switch may also be provided for use by an authorised operator to operate the device. Examples of suitable types of relay circuit are described.